Grate for the furnaces of steam-boilers.



H. scHoFIELD. GRATE FOR THE FURNAOES OF STEAM BOILEBS.

APPLIOATIONTILED NOV. 23, 1907..

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- AHENRY scHoFIELD, oF SHEFFIELD, ENGLAND.

GRATE FORETHE FuRNAcEsoF STEAM-Bomans.

specification@ Leeeersratent.

PatentedrSept. 29, 1908.

" Applicaua mea november 23, 1907. serial N0. 403,466.

To all whom it may concern:` i

Be it known that I, HENRY Sci-Iornm), a subject of the King of Great Britain and Ireland, residing at 267 Stannington road,

city of Sheffield, England, have invented cer-` tain new and usefulfImprovements in Grates forV the Furnaces n of Steam-Boilers, (for which I have applied. for aL patentin Great Britain, No. 1,976, January 26, 1907; France, y

No. 46,138, September 14, 1907 5 Spain, No. 8,261, September 13,1907 Russia, No. 33,416, September 4, 1907,) ofwhichthe following is a specification, reference being had to the accompanying drawing.

This invention relates more particularly to the construction of a furnacefloor the arrangement of the bars in relation to the longitudinal air conduits located underneath them, through which air, or a mixture of air and steam, is supplied for the purposes ofV combustion; and it also` refers to the construction of the furnace bridge. l 'Ihey are illustrated in the annexed sheet of drawings in which L l n V Figure 1, is a plan, and Fig.\2, side elevation of four single furnace bars in position across the two supporting air chambers, and also showing the position of steam pipe and jets. Fig. 3, is a plan, elevation, and underside of a double length furnace bar; Fig. 4,

vertical section of improved bridge. Y

In carrying out that part of the invention referring to the floor of the furnace, a number of trough shaped air conduits A, open at the top and the front end'and' closed at the far end, and havingopenings through the base and a hit-.and-miss slide A2, by which ash and the like can be cleared from the in#` terior, are supported in the furnace of the,

boiler in thevusua'l position of'afurnace floor. These conduitsV receivefcompressed air, or air and steam, fromgpipes A3, pro-` vided `with jet openings,. at the front' end and convey it to'all the `numerous apertures E, through` the oor of the furnace above,

and so into the fuel to promote combustion.`

The floor is composed of furnace bars B, either cast singly as Vthe four shown in Fig. 1, or in multiples-such asthe two shownin Fi 3, connected endwise 'arranged across an supportedby theconduits. yThe single bars are made to reach Vacross andwrest upon the top edges ofy one conduit, and the lower part of the bar toftwithinfit, as

shown, for which purpose the bars are formed with steps or abutments at C. Slightly projecting faces I), are cast on each side of the bars which form abutments for the adjacent bars, and determine the length 4and width of the narrow vertical air passages E, through the floor of the furnace, and also prevent any displacement of the bars in relation to each other. Upon the ends of the bars which are next to the side of the furnace F, areprojections G, to continue the floor surface up to the furnace side. By arranging the furnace bars transversely to `the furnace and to the air conduits, cross bars or like supports (required with longitudinal bars) are dispensed with, as also are the special bars generally required for the furnace sides, and the transverse air openings so constructed give a better result in the regulation of the air-supply to the fuel from end to end of the furnace than do longitudinal openings. v

The second part of my invention relates to the hollow bridge for the additional supply of heated air, in combination with the improved ioor, and is shown in Fig. 4. It consists of a cast iron air passage H, tapering upwards, and open at the top and bottom which is not novel per se, the lower opening being provided with a valve I, to regulate the admission lof air and the front `having ribs or gills.' It has been usual to protect both sides of such metal bridges from the Vburning effects of heat from the fur- Vnace, with brickwork such as J, but it is found from experiments that brickwork facingthe furnace K, is unnecessary, as the current of air passing through the bridge prevents the metal being burned; the air y. passing through is also rendered much hotterv without the brickwork, and consequently is more effective in causing the combustion of the unburned products when passing over `the bridge, I therefore omit the briclrwork onthe furnace side of the upper portion H2 leaving it and its gills L, open `to the action of the fire.

n Having now particularly described my invention, I declare that what I wish to yclaim as novel and protect by Letters Patent, is

In steam boiler furnaces the combination with longitudinally extending trough shaped `air conduits vhaving downwardly converging Walls and having their upper producing vertical tapering air passages edges flanged outwardly, of transversely arsubstantially as described. lo ranged re bars having converging depend- In Witness whereof I have hereunto set ing portions conforming to and fitting iny hand in presence of two witnesses.

5 closely Within the conduits, and having end HENRY SCHOFIELD.

projections Which rest on said conduit Titnessesz flanges, said fire bars being formed With ENsoR D. DRURY,

vertical and inclined spacing abutinents CHARLES DRURY. 

